#!/usr/bin/env python
#
# This script requies OsmApi (http://wiki.openstreetmap.org/wiki/PythonOsmApi)
#
# download:
#	wget http://svn.openstreetmap.org/applications/utils/python_lib/OsmApi/OsmApi.py
# run this script:
#	PYTHONPATH=. python THIS_SCRIPT_NAME <LIST_OF_WAY_IDs_AND_HEIGHTS
#
# The input file should contain the way ids in the first column and the height
# in the second column separated by a space or tab.
#
# Update your username and password below!
#

import OsmApi
import sys
import types

username = u"YOUR_USER_NAME"
password = u"YOUR_PASSWORD"

value_key = u"building:height"
forbidden_tags = [value_key, u"height"]
required_tags = [u"building"]
bounding_box = {
		"min_lat": 54.027,
		"max_lat": 54.197,
		"min_lon": 11.984,
		"max_lon": 12.267,
		}


def remove_trailing_zeros(text):
	value = text
	while (value.find(".") >= 0) and (value.endswith("0") or value.endswith(".")):
		value = value[:-1]
	return value


def process_input_line(line):
	try:
		id, value = line.split()
		# convert the id string into a number
		id = int(id)
		# remove trailing zeros from input number
		value = remove_trailing_zeros(value)
		# all values are in meter
		value += " m"
	except ValueError:
		return None
	return (id, value)
		

def read_id_value_file(filename):
	result = []
	try:
		if type(filename) is types.FileType:
			handle = filename
		else:
			handle = file(filename)
		for line in handle.readlines():
			item = process_input_line(line)
			if item is None:
				sys.stderr.write("Ignored invalid input line: %s\n" % str(line))
			else:
				result.append(item)
		handle.close()
	except IOError, err_msg:
		sys.stderr.write("Failed to open input file (%s): %s\n" % (filename, err_msg))
	return result

def validate_way(way, height, api):
	"""check if the given way is safe to be updated
	returns an error description string or an empty string (-> way is ok)
	"""
	# check for forbidden tags
	for forbid_tag in forbidden_tags:
		if way[u"tag"].has_key(forbid_tag):
			if forbid_tag == value_key:
				if height == way[u"tag"][forbid_tag]:
					return "tag already set correctly"
				else:
					return "tag already contains different value"
			else:
				return "contains forbidden tag '%s'" % forbid_tag
	# check for required tags
	for required_tag in required_tags:
		if not way[u"tag"].has_key(required_tag):
			return "missing required tag '%s'" % required_tag
	# check if all the nodes are within the bounding box
	for node_id in way[u"nd"]:
		node = api.NodeGet(node_id)
		if (node[u"lat"] < bounding_box["min_lat"]) or (node[u"lat"] > bounding_box["max_lat"]):
			return "latitude of node %d out of range" % node_id
		if (node[u"lon"] < bounding_box["min_lon"]) or (node[u"lon"] > bounding_box["max_lon"]):
			return "longitude of node %d out of range" % node_id
	return ""

def update_way(way, height):
	way[u"tag"][value_key] = height
	return way

def send_changeset(api, changes):
	api.ChangesetCreate({u"comment": u"Importing  heights of houses from KVL Rostock"})
	for change in changes:
		api.WayUpdate(change)
	api.ChangesetClose()

if __name__ == "__main__":
	# read the input file content
	input = read_id_value_file(sys.stdin)

	api = OsmApi.OsmApi(username=username, password=password)

	changes = []
	for item in input:
		way = api.WayGet(item[0])
		warning = validate_way(way, item[1], api)
		if not warning:
			changes.append(update_way(way, item[1]))
			print "Accepting valid way (%d/%s): %s" % (item[0], item[1], str(way))
		else:
			print "Ignoring invalid way (%d/%s): %s (%s)" % (item[0], item[1], warning, str(way))
	
	if len(changes) > 0:
		send_changeset(api, changes)